The present invention relates to a method of coating an upsidedown Z-notch in a piece made of nickel alloy, and having a plane wall preceded by a rounded portion. Such pieces may, in particular, be constituted by blades for a gas turbine and be made of a nickel alloy that is difficult to weld.
Mini-plasma and manual TIG methods are much lengthier in use and they depend too much on the operator.
It might be thought that using a method with a very high power laser would enable the layers at the end wall of the notch to be properly bonded, but tests performed have shown that it is not then possible to satisfy the specifications concerning cracking.